Secundus is second-born Stormhold son, who's dead and gone (but still hanging around, like you do).
Quintus is the fifth son of the Lord of Stormhold, and was murdered by Septimus when he slipped poison into "a dish of spiced eels" (3.5). Ick on both counts.
Quartus is another Stormhold son, who's also a ghost, trying to see who'll get the topaz.
Sextus is the fourth son of the Lord of Stormhold, and is also dead by Septimus's hand. Septimus pushed him off a precipice at night.
This airship captain comes to Tristran and Yvaine's rescue when they're stranded in the cloud. He has a "ruddy, mustachioed face" (8.80) and a cheerful disposition, and he captains the Free Ship Perdita, which hunts lightning, among other things.
He makes a reference to a castle, and Tristran catches on. There's apparently a fellowship that goes by that name and includes the hairy little person, and they're all looking out for Tristran and Yvaine. Why they care remains a mystery, as is often the case with secret societies, but we're glad that Tristran has friends in high places (literally—ha, ha).
This woman is the ship medic on the Perdita. She's "a nervous-looking woman with an explosive mop of carrot-red hair" (8.89) and luckily she knows her way around a first-aid kit. She puts goop on Tristran's burned hand, and she helps Yvaine with her broken leg, so the two of them are in better shape in no time.
The first mate on the airship Perdita, he's a little strange, just like his name implies. He's "a quiet gentleman with large wings and a bad stammer" (8.92). Tristran shares his bunk, and that's all we really hear of him.
This dude is Mr. Monday's business partner in their shop, Monday and Brown's. When Tristran wants to walk Victoria home, and asks to take off the rest of that evening, "Mr. Brown grunted in a not entirely ill-natured way and told Tristran that when he was younger he'd not only had to stay late each night and shut up the shop, but that he had also had to sleep on the floor beneath the counter with only his coat for a pillow" (2.45). He sounds like one of those old guys who had to walk uphill in snow both ways to school.
He's one of the guards at the wall when Tristran returns from Faerie, and he stubbornly refuses to let Tristran and Yvaine through, saying, "'Even if you are that good-for-nothing Thorn […] I see no reason to let either of you people through. We guard the wall, after all'" (10.7). Well, okay then. Be that way.
This fellow is "a husky young man several years older than Tristran, the miller's son" (2.120). He's "heard tales" (2.131) of Tristran's origins, and—with some encouragement from Mr. Bromios—stands aside to let Tristran through the wall when he sets off on his adventure.
When the witch-queen, the eldest of the Lilim, sets out to find the star, she leaves behind her two sisters. She gets some youth for her journey, while they remain old, and she eyes "her sisters' hairy chins and hollow eyes with disfavor" (3.92). They're not happy about having to stay home and wait for her to come back with the star.
They're even unhappier, though, when their sister lets the star get away at the inn. As they chat via a unicorn blood pool, the second sister chews the witch-queen out, saying, "'You took the last of the youth we had saved—I tore it from the star's breast myself, long, long ago, though she screamed and writhed and carried on ever-so. From the looks of you, you've squandered most of the youth already'" (8.52). We have a hunch that this isn't going to end well.
This guy is "a choleric gnome of poor disposition" (4.147). He doesn't seem thrilled when the three lords of Stormhold show up and demand lodging and food for the night.
This chick is the pot-girl at the inn where the three lords of Stormhold stop for the night. She must have the second sight or something, because she sees all seven lords of Stormhold standing outside the inn.
Lacey is the ostler (a.k.a. horse handler) at the inn at Nottaway who hears Tilly say that there are ghosts. We don't get to see Lacey's response to this, though.
Letitia is the chambermaid at the inn at Nottaway. Tertius slips her a silver coin, and so she comes to his room late at night for some sexy-times. Unfortunately, she gives Tertius some wine that Septimus gave her in order to help Tertius, ahem, keep performing. It kills him, though, and she screams and screams about it. Primus commands her to escort Tertius's body back to Stormhold.
Poor Brevis. His mom tells him to sell their mean-tempered goat at the market; he is bitten and kicked by the goat in the process; and then when he meets a nice-looking lady who offers him gold for the goat, she turns out to be a witch-queen who transforms him into a goat, too. She turns him back into human later, but as a girl, and "a boyish, dull-eyed young woman" (6.57) at that. Brevis dies after being kicked by the unicorn and its sharp hooves.
This is the goat that Brevis takes to the market to sell, whom the witch-queen later transforms into "a man with a white chin-beard" (6.57). The witch-queen poses as his wife, and "Billy" acts as the innkeeper who isn't very talkative. He meets his end when the unicorn spears him with its horn when all hell breaks loose at the inn.
This is one of Louisa and Victoria's friends, and she shares her opinion in the gossip circle about marriage. She thinks it wouldn't be so bad to marry a widower, saying, "'someone else would have removed the rough edges; broken him in, if you will. Also, I would imagine that by his age his lusts would long since have been dated, and abated, which would free one from a number of indignities'" (2.21). We can guess what she means, and all we're going to say is that Victorian-era England was not renowned for its factual and comprehensive sex education.
This friend of Louisa and Victoria's also has an opinion to share about marriage, specifically, marriage with Mr. Monday, the forty-five-year-old widower. She thinks it'd be neat to share all the swanky parts of his life, like carriage rides and travel, even if he is on the older side.
This cousin of Louisa Thorn has some strong opinions about marriage. When Victoria, Louisa, and some other chicks are talking about how Mr. Monday has a thing for Victoria, Cecilia says she wouldn't want to marry someone who's already been married because "'It would be […] like having someone else break in one's own pony'" (2.20). That's certainly one way to think about it.
This fellow is "a huge man with dark eyes and a small, chittering monkey" (1.26). Alum Bey doesn't speak much English, but he has a thing for Bridget Comfrey, which leads to a fight between him and Tommy Forester.
Daisy Hempstock's family puts up a "very tall gentleman with a very long black beard" (1.43) at the Faerie Market where Dunstan buys the glass snowdrop for Daisy. He doesn't speak much English, and whenever Daisy and her female relatives pass by, the man bows to them, after which he "returned to his pack of wooden oddments, sorting, arranging, and polishing" (1.43). Seems like he's yet another example of the weird but generally harmless people who descend on Wall for the market.
This guy is described as a "taller ebony-colored gentleman in the white one-piece robe" (1.52) with whom Dunstan's soon-to-be-lodger is dining at the inn. He gets called away, prompting the gentleman in the black top hat to start up a convo with Dunstan.
When Tristran is on the verge of starvation while traveling with the star and the unicorn, he has to go into a village to look for food. He meets a "portly old woman who […] insisted he accompany her to her cottage, where she pressed upon him a wooden bowlful of barley porridge with carrots in it, and a mug of small beer" (5.145). She accepts a nice handkerchief from him in exchange for some food to go, and generally seems like a nice person, which is great since it means Faerie's not just full of villains and weirdos.
After Tristran is turned back from the wall on his return, he and Yvaine wander back through the market as it's being set up. They "stopped and watched a small woman, almost as broad as she was high, do her best to put up her stall" (10.17), so Tristran helps her out with everything, and in return she feeds him dinner. She also gives him enough wine that he crashes out for the night, leaving Yvaine free to talk to the slave-girl who had been a bird.
This is one of the guys guarding the wall when Tristran returns from Faerie. He "had once been Tristran's schoolfellow, although never his friend" (10.2), and he defers to Mr. Brown's decision to not let Tristran back through the wall, making us think that he's not one to think for himself.
The vicar of Wall is someone whom Tristran had always regarded "with some awe" (10.54), so when the vicar shows up to greet him when he returns from Faerie, it's pretty neat.